Polymer, Resist Composition, Method for Manufacturing Substrate Having Pattern Formed Therein, and (Meth)Acrylic Ester and Production Method Therefor

ABSTRACT

Provided is a polymer including a constituent unit (1) based on a monomer represented by Formula (1), in which a content of a constituent unit based on a monomer having a polycyclic structure is 35 mol % or less. In Formula (1), R1 represents a hydrogen atom or a methyl group, A1 represents a linking group including an ester bond, or a single bond, where A1 has no tertiary carbon atom, and Z1 represents an atomic group forming a sulfur-containing cyclic hydrocarbon group having 3 to 6 carbon atoms, which includes a carbon atom bonded to A1, and —SO2—.

TECHNICAL FIELD

The present invention relates to a polymer, a resist compositionincluding the polymer, a method for manufacturing a substrate having apattern therein using the resist composition, a (meth)acrylic ester, anda production method of the (meth)acrylic ester.

Priority is claimed on Japanese Patent Application No. 2019-059909,Japanese Patent Application No. 2019-059910, and Japanese PatentApplication No. 2019-060490, filed Mar. 27, 2019, the contents of whichare incorporated herein by reference.

BACKGROUND ART

A (meth)acrylic ester containing a sulfonyl group (hereinafter, may bereferred to as a “sulfonyl group-containing (meth)acrylic ester”) isknown as a sulfur-containing monomer. A polymer obtained byhomopolymerizing the sulfonyl group-containing (meth)acrylic ester or acopolymer obtained by copolymerizing the sulfonyl group-containing(meth)acrylic ester with another monomer may be used, for example, as amaterial having a high dielectric constant, a material having a highrefractive index, or a medical adhesive having an anti-inflammatoryeffect.

As a production method of such a sulfonyl group-containing (meth)acrylicester, a method by ester exchange reaction between a (meth)acrylic esterand an alcohol is known (for example, Patent Document 1).

As an exposure light source of lithography used for manufacturingsemiconductors, the wavelength has been shortened, and as anext-generation exposure light source, mass production of semiconductordevices using an ArF excimer laser having a wavelength of 193 nm orextreme ultraviolet (EUV) having a wavelength of 13.5 nm, which hashigher energy, is progressing.

It is desirable that a resist polymer adopted to these include a polargroup from the viewpoint of adhesiveness to a substrate and affinity fora polar solvent. In the related art, as a monomer including such a polargroup, a (meth)acrylic ester containing a lactone group has been widelyused.

The sulfonyl group-containing (meth)acrylic ester has high polarity, sothat it is expected that the sulfonyl group-containing (meth)acrylicester can also be adopted as the monomer (raw material monomer)constituting the resist polymer.

When producing the resist polymer using the sulfonyl group-containing(meth)acrylic ester as the monomer, in a case where ahigh-molecular-weight substance is mixed in the sulfonylgroup-containing (meth)acrylic ester, the high-molecular-weightsubstance may be insoluble matter and defects may occur duringdevelopment. Therefore, it is necessary to reduce the content of thehigh-molecular-weight substance as much as possible.

As a resist composition which can be suitably used for shortening thewavelength of irradiation light and miniaturizing a pattern inlithography technology, a chemically amplified resist composition isknown. The chemically amplified resist composition includes a resistpolymer from which an acid-eliminating group is eliminated by action ofan acid, and a photoacid generator.

In recent years, pattern miniaturization has progressed rapidly, and itis desired to develop a resist material capable of further improvingvarious lithography characteristics such as sensitivity, patternformability, and line width roughness (LWR).

In Comparative Examples of Patent Document 2, a polymer obtained bypolymerizing a mixture of a monomer represented by Formula (a1-1-2), amonomer represented by Formula (a2-1-1), a monomer represented byFormula (a3-1-1), and a monomer represented by Formula (I-2) in a molarratio of 30:20:40:10 is disclosed. In addition, when a resist pattern isformed using the resist composition containing the polymer and the acidgenerator, it is disclosed that roughness occurs on the side surface ofthe pattern and the line width roughness (LWR) is inferior.

CITATION LIST Patent Documents

Patent Document 1

Japanese Unexamined Patent Application, First Publication No.2007-153763

Patent Document 2

Japanese Unexamined Patent Application, First Publication No.2012-234166

SUMMARY OF INVENTION Technical Problem

When a sulfonyl group-containing (meth)acrylic ester is produced by anester exchange method as in Patent Document 1, in order to tilt theequilibrium toward the product, alcohols, such as methanol, produced bythe reaction are extracted by distillation. Therefore, it is necessaryto raise the reaction temperature to a high temperature.

As a result of studies, the present inventors have found that thesulfonyl group-containing (meth)acrylic ester is highly polymerizable,and when the sulfonyl group-containing (meth)acrylic ester is exposed toa high temperature in the ester exchange reaction, ahigh-molecular-weight substance is produced by the polymerization of thesulfonyl group-containing (meth)acrylic ester.

Patent Document 1 discloses that the product is purified byrecrystallization, washing, or the like, but with such a method, thehigh-molecular-weight substance cannot be sufficiently removed.

In addition, in a resist composition including a polymer having anacid-eliminating group, improvement of LWR can be expected by improvingsolubility of the polymer in a developer.

An object of the present invention is to provide a polymer havingexcellent solubility in a developer, to provide a resist compositionincluding the polymer, to provide a method for manufacturing a substratehaving a pattern therein using the resist composition, to provide a(meth)acrylic ester in which a high-molecular-weight substance isreduced, and to provide a production method of a (meth)acrylic ester inwhich a high-molecular-weight substance is reduced.

Solution to Problem

The present invention has the following aspects.

[1] A polymer including:

a constituent unit (1) based on a monomer represented by Formula (1),

in which a content of a constituent unit based on a monomer having apolycyclic structure is 35 mol % or less.

In Formula (1), R¹ represents a hydrogen atom or a methyl group, A¹represents a linking group including an ester bond, or a single bond,where A¹ has no tertiary carbon atom, and Z¹ represents an atomic groupforming a sulfur-containing cyclic hydrocarbon group having 3 to 6carbon atoms, which includes a carbon atom bonded to A¹, and —SO₂—.

[2] The polymer according to [1], further including:

a constituent unit (2) having an acid-eliminating group.

[3] The polymer according to [2],

in which the constituent unit (2) includes a constituent unit (2i) whichhas an acid-eliminating group including an alicyclic hydrocarbon group.

[4] The polymer according to [3],

in which the constituent unit (2) includes a constituent unit (2ii)which has an acid-eliminating group including a monocyclic alicyclichydrocarbon group.

[5] The polymer according to any one of [1] to [4],

in which the constituent unit (1) is 15 mol % or more with respect toall constituent units.

[6] The polymer according to any one of [1] to [5], further including:

a constituent unit (3) having a lactone skeleton.

[7] A resist composition including:

the polymer according to any one of [1] to [6]; and a compoundgenerating acid by irradiation with active light or radiation.

[8] A method for manufacturing a substrate having a pattern formedtherein, including:

a step of applying the resist composition according to [7] to a surfaceof a substrate to be processed to form a resist film;

a step of exposing the resist film; and

a step of developing the exposed resist film with a developer.

[9] A production method of a (meth)acrylic ester represented by Formula(1x), including:

a step 1: step of performing an ester exchange reaction between analcohol represented by Formula (2x) and a (meth)acrylic esterrepresented by Formula (3x) to obtain a solution including a(meth)acrylic ester (lx) represented by Formula (1x); and

a step 2: step of adding a poor solvent to the solution including the(meth)acrylic ester (1x) obtained in the step 1 to precipitate ahigh-molecular-weight substance, and removing the high-molecular-weightsubstance.

In Formula (Ix), R¹¹ represents a hydrogen atom or a methyl group, A¹¹represents a linking group including an ester bond, or a single bond,where A¹¹ has no tertiary carbon atom, and Z¹¹ represents an atomicgroup forming a sulfur-containing cyclic hydrocarbon group having 3 to 6carbon atoms, which includes a carbon atom bonded to A¹¹, and —SO₂—.

In Formula (2x), Z¹¹ represents an atomic group forming asulfur-containing cyclic hydrocarbon group having 3 to 6 carbon atoms,which includes a carbon atom bonded to a hydroxy group, and —SO₂—.

In Formula (3x), R¹¹ represents a hydrogen atom or a methyl group, andR¹² represents a linear or branched alkyl group having 1 to 10 carbonatoms.

[10] The production method of a (meth)acrylic ester according to [9],

in which a hydrocarbon solvent is used as the poor solvent in the step2.

[11] A (meth)acrylic ester represented by Formula (1x), in which acontent of a high-molecular-weight substance having a molecular weightof 5000 or more is 0.1 mass % or less.

In Formula (1x), R¹¹ represents a hydrogen atom or a methyl group, A¹¹represents a linking group including an ester bond, or a single bond,where A¹¹ has no tertiary carbon atom, and Z¹¹ represents an atomicgroup forming a sulfur-containing cyclic hydrocarbon group having 3 to 6carbon atoms, which includes a carbon atom bonded to A¹¹, and —SO₂—.

Advantageous Effects of Invention

According to the present invention, it is possible to provide a polymerhaving favorable solubility in a developer, a resist compositionincluding the polymer, and a method for manufacturing a substrate havinga pattern formed therein using the resist composition.

According to the present invention, it is possible to provide a sulfonylgroup-containing (meth)acrylic ester in which a high-molecular-weightsubstance is reduced.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described in detail below.

Definitions of the following terms apply throughout the specificationand claims.

In the present specification, “(meth)acrylic acid” means one or both ofacrylic acid and methacrylic acid.

In the present specification, “constituent unit” means an atomic groupformed by a polymerization reaction of monomers.

In the present specification, a monomer represented Formula (1) may bereferred to as a monomer (1). The same applies to monomers representedby other formulae.

In the present specification, a compound represented by Formula (1) maybe referred to as a compound (1). The same applies to compoundsrepresented by other formulae.

<Polymer>

A polymer according to the present embodiment (hereinafter, alsoreferred to as a “polymer A”) includes a constituent unit (1) based on amonomer (1) represented by Formula (1). The content of a constituentunit based on a monomer having a polycyclic structure is 35 mol % orless with respect to all constituent units of the polymer A.

It is preferable that the polymer A further include one or moreconstituent units (2) having an acid-eliminating group. The polymer Amay include one or more constituent units other than the constituentunits (1) and (2).

The polymer A is suitable as a resist polymer.

[Constituent Unit (1)]

The constituent unit (1) is a constituent unit formed by cleaving anethylenic double bond of the monomer (1).

In Formula (1), R¹ represents a hydrogen atom or a methyl group.

A¹ is a linking group including an ester bond, or a single bond.However, A¹ has no tertiary carbon atom. Examples of the linking groupinclude -A²-C(═O)O— and -A³-O—C(═O)—. A² and A³ are divalent chain-likehydrocarbon groups having 1 to 5 carbon atoms. The chain-likehydrocarbon groups as A² and A³ may be linear or branched. A² and A³ arepreferably an alkylene group having 1 to 3 carbon atoms. A² and A³ haveno tertiary carbon atom.

Z¹ is an atomic group forming a sulfur-containing cyclic hydrocarbongroup (4-membered ring to 7-membered ring) having 3 to 6 carbon atoms,which includes a carbon atom bonded to A¹, and —SO₂—. From the viewpointof the stability of the cyclic structure, the sulfur-containing cyclichydrocarbon group preferably has 4 to 6 carbon atoms. In addition, asubstituent may be bonded to a carbon atom constituting a ring of thesulfur-containing cyclic hydrocarbon group. Examples of the substituentinclude a linear or branched alkyl group having 1 to 10 carbon atoms, ahydroxy group, an amino group, an aldehyde group, a chloro group, abromo group, and an iodo group.

As the monomer (1), an aspect in which a substituent is not bonded tothe carbon atom constituting the ring of the sulfur-containing cyclichydrocarbon group, or an alkyl group having 1 to 6 carbon atoms isbonded thereto as a substituent is preferable. The monomer of thisaspect is represented by Formula (1′).

In Formula (1′), R¹ and A¹ are the same as R¹ and A¹ in Formula (1).

n represents an integer of 1 to 4. A heterocycle bonded to A¹ is, forexample, a 4-membered ring when n is 1, and a 7-membered ring when n is4. From the viewpoint of stability and ease of synthesis, n ispreferably 2.

R² represents a substituent bonded to a carbon atom constituting theabove-described heterocycle. However, R² is not bonded to the carbonatom bonded to A¹.

m of R² each independently represents an alkyl group having 1 to 6carbon atoms. The alkyl group may be linear or branched. When m is 2 ormore, a plurality of R² existing in one molecule may be the same as ordifferent from each other.

m is an integer of 0 or more and (n+1) or less, and is preferably aninteger of 0 or more and n or less, more preferably 0 or 1, and mostpreferably 0.

Examples of a group bonded to A¹ include groups represented by Formulae(la) to (1d). * in the formulae represents a bonding position to A¹.

As the monomer (1), an aspect in which R¹ is a hydrogen atom or a methylgroup, A¹ is a single bond, and any one of the groups represented byFormulae (la) to (1d) is bonded to A¹ is preferable.

Among the groups represented by Formulae (1a) to (1d), from theviewpoint of stability and ease of synthesis, the group represented byFormula (1b) is particularly preferable.

The constituent unit (1) included in the polymer A may be one kind ortwo or more kinds.

The constituent unit (1) is preferably 15 mol % or more, more preferably20 mol % or more, and still more preferably 25 mol % or more withrespect to all constituent units of the polymer A. From the viewpoint ofsensitivity and resolution, the upper limit is preferably 70 mol % orless, more preferably 60 mol % or less, and still more preferably 50 mol% or less.

For example, the constituent unit (1) is preferably 15 to 70 mol %, morepreferably 20 to 60 mol %, still more preferably 25 to 60 mol %, andparticularly preferably 25 to 50 mol % with respect to all constituentunits of the polymer A.

[Constituent unit (2)]

The constituent unit (2) is a constituent unit based on a monomer(hereinafter, also referred to as a monomer (2)) having anacid-eliminating group. The acid-eliminating group is a group having abond which is cleaved by action of an acid, and is a group in which apart or all of the acid-eliminating group is eliminated from the polymerby the cleavage of the bond. In a positive type chemically amplifiedresist composition, by heating after exposure, an acid-eliminating groupof the polymer in an exposed portion reacts with the acid to beeliminated, and the polymer is soluble in an alkaline developer.

The monomer (2) is preferably a (meth)acrylic ester compound. As the(meth)acrylic ester compound having an acid-eliminating group, a knowncompound can be used.

From the viewpoint of dry etching resistance in the lithography process,the monomer (2) preferably includes a (meth)acrylic ester compound whichhas an acid-eliminating group including an alicyclic hydrocarbon group.

The above-described alicyclic hydrocarbon group may be monocyclic orpolycyclic. The above-described alicyclic hydrocarbon group may includea heteroatom. The above-described heteroatom is preferably one or moreatoms selected from the group consisting of O, S, and N. The number ofatoms constituting the ring is preferably 5 to 22.

From the viewpoint that sensitivity and resolution of a resist areexcellent, it is more preferably an acrylic ester which has a tertiarycarbon atom at a bonding site with an oxygen atom constituting the esterbond of acrylic ester. Specific examples thereof include monomers (2-1)to (2-4) of the following formulae.

In particular, from the viewpoint that, when combined with theconstituent unit (1), the effect of improving solubility in a developercan be easily obtained, the monomer (2-4) is more preferable.

In Formulae (2-1) to (2-4), R³¹, R³², R³³, and R³⁴ each independentlyrepresents a hydrogen atom or a methyl group.

R²¹, R²⁴, and R²⁵ each independently represents an alkyl group having 1to 5 carbon atoms. The alkyl group may be linear or branched.

R²² and R²³ each independently represents an alkyl group having 1 to 3carbon atoms. The alkyl group may be linear or branched.

R³³¹, R³³², R³³³, and R³³⁴ each independently represents a hydrogen atomor an alkyl group having 1 to 6 carbon atoms. The alkyl group may belinear or branched.

X¹, X², X³, and X⁴ each independently represents an alkyl group having 1to 6 carbon atoms. The alkyl group may be linear or branched.

n1, n2, n3, and n4 each independently represents an integer of 0 to 4.When n1, n2, n3, or n4 is 2 or more, a plurality of X¹, X², X³, or X⁴existing in one molecule may be the same as or different from eachother.

Z² and Z³ each independently represents —O—, —S—, —NH—, or —(CH₂)_(k)—.k represents an integer of 1 to 6.

q represents 0 or 1.

r represents an integer of 0 to 3.

The constituent unit (2) included in the polymer A may be one kind ortwo or more kinds.

The constituent unit (2) is preferably 20 to 80 mol %, more preferably30 to 70 mol %, and still more preferably 40 to 60 mol % with respect toall constituent units of the polymer A. In a case of being the lowerlimit value or more of the above-described range, favorable sensitivitycan be easily obtained, and in a case of being the upper limit value orless, it is easy to obtain a favorable balance as a resist and it iseasy to obtain favorable adhesiveness to a substrate.

The constituent unit (2) preferably includes a constituent unit (2i)which has an acid-eliminating group including an alicyclic hydrocarbongroup. The above-described alicyclic hydrocarbon group may be monocyclicor polycyclic. The above-described alicyclic hydrocarbon group mayinclude a heteroatom. The above-described heteroatom is preferably oneor more atoms selected from the group consisting of 0, S, and N. Thenumber of atoms constituting the ring is preferably 5 to 22.

The content of the constituent unit (2i) is preferably 25 mol % or more,more preferably 35 mol % or more, still more preferably 50 mol % ormore, and particularly preferably 75 mol % or more with respect to thetotal number of moles of the constituent unit (2). The content of theconstituent unit (2i) may be 100 mol %. When the content of theconstituent unit (2i) is the above-described lower limit value or more,when combined with the constituent unit (1), the effect of improvingsolubility in a developer can be easily obtained.

The constituent unit (2) more preferably includes a constituent unit(2ii) which has an acid-eliminating group including a monocyclicalicyclic hydrocarbon group. The above-described monocyclic alicyclichydrocarbon group preferably does not include a heteroatom. The numberof atoms constituting the ring of the above-described monocyclicalicyclic hydrocarbon group is more preferably 5 to 8 and still morepreferably 5 or 6. For example, a constituent unit based on theabove-described monomer (2-4) is more preferable.

The content of the constituent unit (2ii) is preferably 25 mol % ormore, more preferably 35 mol % or more, still more preferably 50 mol %or more, and particularly preferably 75 mol % or more with respect tothe total number of moles of the constituent unit (2). The content ofthe constituent unit (2ii) may be 100 mol %. When the content of theconstituent unit (2ii) is the above-described lower limit value or more,when combined with the constituent unit (1), the effect of improvingsolubility in a developer can be easily obtained.

The content of a constituent unit based on a monomer having a polycyclicstructure is 35 mol % or less, more preferably 30 mol % or less withrespect to all constituent units of the polymer A. When the constituentunit having a polycyclic structure is 35 mol % or less, solubility ofthe polymer A in a developer is excellent.

[Other Constituent Units]

As other constituent units, a known constituent unit in the chemicallyamplified resist composition can be used. Examples thereof include aconstituent unit having a lactone skeleton and a constituent unit havinga hydrophilic group.

(Constituent Unit Having Lactone Skeleton (Hereinafter, Also Referred toas Lactone Unit))

The lactone skeleton means a monocyclic or polycyclic atomic groupincluding a ring having —O—C(═O)—. The above-described ring having—O—C(═O)— may be a ring having —C(═O)—O—C(═O)—.

The lactone skeleton is preferably a 4- to 20-membered ring and morepreferably a 5- to 10-membered ring.

The lactone skeleton may be a monocycle having only a lactone ring, oran aromatic or non-aromatic hydrocarbon ring or heterocycle may becondensed on the lactone ring.

As the monomer having a lactone skeleton, a (meth)acrylic ester compoundis preferable. In particular, from the viewpoint that adhesiveness to asubstrate or the like is excellent, at least one selected from the groupconsisting of (meth)acrylic ester having a substituted or unsubstitutedδ-valerolactone ring and (meth)acrylic ester having a substituted orunsubstituted γ-butyrolactone ring is preferable, and a monomer havingan unsubstituted γ-butyrolactone ring is particularly preferable.

Specific examples of the monomer having a lactone skeleton includeβ-(meth)acryloyloxy-β-methyl-δ-valerolactone,4,4-dimethyl-2-methylene-γ-butyrolactone,β-(meth)acryloyloxy-γ-butyrolactone,β-(meth)acryloyloxy-β-methyl-γ-butyrolactone,α-(meth)acryloyloxy-γ-butyrolactone,2-(1-(meth)acryloyloxy)ethyl-4-butanolide, (meth)acrylic pantoyllactone, 5-(meth)acryloyloxy-2,6-norbornane carbolactone,8-methacryloxy-4-oxatricyclo[5.2.1.0^(2,6)] decan-3-one, and9-methacryloxy-4-oxatricyclo[5.2.1.0^(2,6)]decan-3-one.

The lactone unit included in the polymer A may be one kind or two ormore kinds.

When the polymer A includes the lactone unit, the content thereof ispreferably 10 to 70 mol %, more preferably 20 to 60 mol %, and stillmore preferably 30 to 50 mol % with respect to all constituent units ofthe polymer A. In a case of being within the above-described range, theeffect of improving adhesiveness to a substrate can be easily obtained.

(Constituent Unit Having Hydrophilic Group (Hereinafter, Also Referredto as Hydrophilic Unit))

The “hydrophilic group” in the present specification is one or moreselected from the group consisting of —C(CF₃)₂—OH, a hydroxy group, acyano group, a methoxy group, a carboxy group, and an amino group.

As the monomer having a hydrophilic group, a (meth)acrylic estercompound or a styrene derivative having a hydroxy group is preferable.

Specific examples of the monomer having a hydrophilic group include(meth)acrylic acid, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl(meth)acrylate, 2-hydroxy-n-propyl (meth)acrylate, 4-hydroxybutyl(meth)acrylate, 3-hydroxyadamantyl (meth)acrylate, 2- or3-cyano-5-norbornyl (meth)acrylate, 2-cyanomethyl-2-adamantyl(meth)acrylate, p-hydroxystyrene, and dihydroxystyrene.

From the viewpoint of adhesiveness to a substrate or the like,3-hydroxyadamantyl (meth)acrylate, 3,5-dihydroxyadamantyl(meth)acrylate, 2- or 3-cyano-5-norbornyl (meth)acrylate,2-cyanomethyl-2-adamantyl (meth)acrylate, or the like is preferable.

The hydrophilic unit included in the polymer A may be one kind or two ormore kinds.

The constituent unit having a hydrophilic group contributes toimprovement of wettability of the polymer A to a developer. The contentof the constituent unit having a hydrophilic group is preferably 0 to 40mol %, more preferably 5 to 30 mol %, and still more preferably 10 to 20mol % with respect to all constituent units of the polymer A. In a caseof being within the above-described range, a favorable balance as aresist can be easily obtained.

Examples of a preferred aspect of the polymer A include the followingaspects (i) to (iv).

(i) polymer including the constituent unit (1) and the constituent unit(2), in which the constituent unit (1) is 15 to 70 mol % and theconstituent unit (2) is 20 to 80 mol % with respect to all constituentunits, and the total thereof is 35 to 100 mol %

(ii) polymer including the constituent unit (1), the constituent unit(2), and the lactone unit, in which, with respect to all constituentunits, the constituent unit (1) is 15 to 70 mol %, the lactone unit is10 to 70 mol %, the total of the constituent unit (1) and the lactoneunit is 25 to 85 mol %, the constituent unit (2) is 20 to 80 mol %, andthe total of the constituent unit (1), the constituent unit (2), and thelactone unit is 45 to 100 mol %

(iii) polymer including the constituent unit (1), the constituent unit(2), and the hydrophilic unit, in which, with respect to all constituentunits, the constituent unit (1) is 15 to 70 mol %, the hydrophilic unitis 0 to 40 mol %, the total of the constituent unit (1) and thehydrophilic unit is 15 to 80 mol %, the constituent unit (2) is 20 to 80mol %, and the total of the constituent unit (1), the constituent unit(2), and the hydrophilic unit is 35 to 100 mol %

(iv) polymer including the constituent unit (1), the constituent unit(2), the lactone unit, and the hydrophilic unit, in which, with respectto all constituent units, the constituent unit (1) is 15 to 70 mol %,the lactone unit is 10 to 70 mol %, the hydrophilic unit is 0 to 40 mol%, the total of the constituent unit (1), the lactone unit, and thehydrophilic unit is 25 to 85 mol %, the constituent unit (2) is 25 to 80mol %, and the total of the constituent unit (1), the constituent unit(2), the lactone unit, and the hydrophilic unit is 50 to 100 mol %

The polymer A can be produced, for example, by a solution polymerizationmethod in which a monomer is radically polymerized using apolymerization initiator in the presence of a polymerization solvent.

The weight average molecular weight of the polymer A is preferably 1,000to 100,000, more preferably 3,000 to 50,000, and still more preferably5,000 to 30,000.

<Resist Composition>

A resist composition according to the present embodiment preferablyincludes the polymer A, a resist solvent, and a compound generating acidby irradiation with active light or radiation. One kind of the polymer Amay be used, or two or more kinds thereof may be used in combination.

The content of the polymer A with respect to the resist composition(excluding the solvent) is not particularly limited, but is preferably70 to 99.9 mass %.

Examples of the resist solvent include cyclopentanone, cyclohexanone,propylene glycol monomethyl ether acetate (PGMEA), and propylene glycolmonomethyl ether (PGME). One kind of the resist solvent may be used, ortwo or more kinds thereof may be used in combination.

The amount of the resist solvent used depends on a thickness of a resistfilm to be formed, but is preferably 100 to 10,000 parts by mass withrespect to 100 parts by mass of the polymer A.

The compound generating acid by irradiation with active light orradiation can be optionally selected from those which can be used as aphotoacid generator of the chemically amplified resist composition. Onekind of the photoacid generator may be used, or two or more kindsthereof may be used in combination.

Examples of the photoacid generator include onium salt compounds,sulfonimide compounds, sulfone compounds, sulfonic acid ester compounds,quinonediazide compounds, and diazomethane compounds.

The amount of the photoacid generator used is preferably 0.1 to 20 partsby mass and more preferably 0.5 to 10 parts by mass with respect to 100parts by mass of the polymer A.

The resist composition may include various additives such as anitrogen-containing compound, an acid compound (organic carboxylic acid,and oxo acid of phosphorus or a derivative thereof), a surfactant, otherquenchers, a sensitizer, an anti-halation agent, a storage stabilizer,and a defoamer, as necessary. As the above-described additives, thoseknown in the field of resist compositions can be used.

<Method for Manufacturing Substrate Having Pattern Formed Therein>

An example of a method for manufacturing a substrate having a patternformed therein according to the present embodiment will be described.

First, the resist composition is applied to a surface (surface to beprocessed) of a substrate to be processed such as a silicon wafer byspin coating or the like. The substrate to be processed, to which theresist composition has been applied, is dried by a baking treatment(pre-baking) or the like to form a resist film on the substrate.

Next, the resist film is irradiated with light having a wavelength of250 nm or less through a photomask to form a latent image (exposure). Asirradiation light, KrF excimer laser, ArF excimer laser, F₂ excimerlaser, or EUV excimer laser is preferable, and ArF excimer laser isparticularly preferable. In addition, the resist film may be irradiatedwith an electron beam.

In addition, a liquid immersion exposure in which the resist film isirradiated with light in a state in which a high refractive index liquidsuch as pure water, perfluoro-2-butyl tetrahydrofuran, andperfluorotrialkylamine is interposed between the resist film and a finallens of an exposure apparatus may be performed.

After the exposure, heat treatment (post-exposure baking, PEB) isperformed as appropriate, and a developer is brought into contact withthe resist film to dissolve a part of the resist film. In the positivedevelopment process, an exposed portion is dissolved and removed with analkaline developer.

In the polymer A, the bond of the acid-eliminating group is cleaved byacid generated by the exposure, and the dissolution rate of the exposedportion in the alkaline developer is increased.

As the alkaline developer, an alkaline aqueous solution is used.Examples thereof include aqueous solutions of inorganic alkalis such assodium hydroxide, potassium hydroxide, sodium carbonate, sodiumsilicate, sodium metasilicate, and aqueous ammonia; primary amines suchas ethylamine and n-propylamine; secondary amines such as diethylamineand di-n-butylamine; tertiary amines such as triethylamine andmethyldiethylamine; alcohol amines such as dimethylethanolamine andtriethanolamine; quaternary ammonium salts such as tetramethylammoniumhydroxide and tetraethylammonium hydroxide; and cyclic amines such aspyrrole and piperidine.

After the development, the substrate is appropriately rinsed with purewater or the like. In this way, a resist pattern is formed on thesubstrate to be processed.

The substrate having a resist pattern therein is appropriatelyheat-treated (post-baked) to strengthen the resist, and a portionwithout the resist is selectively dry-etched.

After dry etching, the resist is removed with a release agent to obtaina substrate having a fine pattern therein.

<(Meth)acrylic Ester>

A (meth)acrylic ester according to the present embodiment is a sulfonylgroup-containing (meth)acrylic ester (compound (1x)) represented byFormula (1x), in which the content of a high-molecular-weight substancehaving a molecular weight of 5000 or more is 0.1 mass % or less.

In Formula (1x), R¹¹ represents a hydrogen atom or a methyl group, A¹¹represents a linking group including an ester bond, or a single bond,where A¹¹ has no tertiary carbon atom, and Z¹¹ represents an atomicgroup forming a sulfur-containing cyclic hydrocarbon group having 3 to 6carbon atoms, which includes a carbon atom bonded to A¹¹, and —SO₂—.

Here, the (meth)acrylic ester according to the present embodiment, inwhich the content of the high-molecular-weight substance having amolecular weight of 5000 or more is defined, may be referred to as a“(meth)acrylic ester composition” instead of the “(meth)acrylic ester”,but in the (meth)acrylic ester according to the present embodiment, thehigh-molecular-weight substance (hereinafter, may be simply referred toas a “high-molecular-weight substance”) having a molecular weight of5000 or more is contained in a very small amount of 0.1 mass % or less,or the content thereof is below a detection limit and thehigh-molecular-weight substance is almost non-existent. In addition,since (meth)acrylic ester having a high-molecular-weight substancecontent of 0.1 mass % or less is regarded as a “(meth)acrylic esterproduct” and is further used for various purposes, in the presentembodiment, such a (meth)acrylic ester containing a very small amount oralmost no high-molecular-weight substance is referred to as the“(meth)acrylic ester”.

In addition, as described above, having a high-molecular-weightsubstance content of 0.1 mass % includes the high-molecular-weightsubstance content being below the detection limit in the analysis of thehigh-molecular-weight substance and being substantially 0 mass %.

[Compound (1x)]

In Formula (1x), A¹¹ is a linking group including an ester bond, or asingle bond.

However, A¹¹ has no tertiary carbon atom. The linking group including anester bond as A¹¹ is the same as the linking group including an esterbond as A¹ described above. From the viewpoint of easy availability ofraw materials and ease of synthesis, A¹¹ is preferably a single bond.

R¹¹ is a hydrogen atom or a methyl group, and is preferably a methylgroup.

Z¹¹ is an atomic group forming a sulfur-containing cyclic hydrocarbongroup (4-membered ring to 7-membered ring) having 3 to 6 carbon atoms,which includes a carbon atom bonded to A¹¹, and —SO₂—. From theviewpoint of the stability of the cyclic structure, thesulfur-containing cyclic hydrocarbon group preferably has 4 to 6 carbonatoms. In addition, a substituent may be bonded to a carbon atomconstituting a ring of the sulfur-containing cyclic hydrocarbon group.Examples of the substituent include a linear or branched alkyl grouphaving 1 to 10 carbon atoms, a hydroxy group, an amino group, analdehyde group, a chloro group, a bromo group, and an iodo group.

From the viewpoint of easy availability of raw materials and stabilityof the compound, the sulfur-containing cyclic hydrocarbon group is morepreferably a 2-sulfolane or 3-sulfolane structure in which a ringincluding a sulfonyl group is a 5-membered ring, and among these, a3-sulfolane structure is most preferable.

As the compound (1x), 3-sulfolanyl methacrylate is most preferable.

[High-Molecular-Weight Substance]

In the present embodiment, the content of the high-molecular-weightsubstance in the (meth)acrylic ester can be analyzed by a methoddescribed in the section of Examples described later, and the detectionlimit thereof is 0.03 mass % or less.

The high-molecular-weight substance in the (meth)acrylic ester accordingto the present embodiment is a high-molecular-weight substance producedby polymerizing or copolymerizing a (meth)acrylic ester having asulfonyl group, which is a target substance (compound (1x)) in a step 1of the production method of a (meth)acrylic ester described later, or acompound (3x) described later, which is a raw material for producing thecompound (1x), due to their high polymerizable property. The molecularweight thereof is 5000 or more, and the weight average molecular weight(Mw) thereof measured by a method described in the section of Examplesdescribed later is approximately 3×10⁵ to 6×10⁵. In a case of ahigh-molecular-weight substance having a molecular weight of less than5000, since the high-molecular-weight substance is soluble in a solvent,the high-molecular-weight substance remains in a mother liquor byrecrystallization or the like to be removed. Therefore, thehigh-molecular-weight substance is not a target for removal in a step 2described later.

The content of the high-molecular-weight substance in the (meth)acrylicester according to the present embodiment is preferably small as much as0.1 mass % or less, preferably 0.05 mass % or less, more preferably 0.03mass % or less, and most preferably in an amount below the detectionlimit.

The (meth)acrylic ester according to the present embodiment, in whichthe content of the high-molecular-weight substance is reduced in thismanner, can be produced by the production method of a (meth)acrylicester according to the present embodiment described later.

[Application]

The (meth)acrylic ester according to the present embodiment, in whichthe content of the high-molecular-weight substance is reduced, canexhibit the original excellent properties of the sulfonylgroup-containing (meth)acrylic ester without being affected by thehigh-molecular-weight substance. For example, the (meth)acrylic esteraccording to the present embodiment is useful for a wide range ofapplications such as plastic raw materials, paints, and adhesives.

In particular, the sulfonyl group-containing (meth)acrylic esteraccording to the present embodiment is useful for a resist application,for example, as a monomer constituting an ArF resist polymer. By usingthe monomer having a reduced content of the high-molecular-weightsubstance, lithography characteristics of the resist polymer can beimproved. For example, solubility and developability of the resistpolymer can be improved, and defects during development due to thehigh-molecular-weight substance can be prevented. In addition, due tothe sulfonyl group, adhesiveness to a substrate and affinity for a polarsolvent can be improved.

The sulfonyl group-containing (meth)acrylic ester according to thepresent embodiment can be suitably used as the above-described monomer(1) constituting the above-described polymer A.

<Production Method of (Meth)Acrylic Ester>

A production method of a (meth)acrylic ester according to the presentembodiment is a method for producing the (meth)acrylic ester representedby Formula (1x), and includes the following steps 1 and 2.

Step 1: step of performing an ester exchange reaction between an alcoholrepresented by Formula (2x) and a (meth)acrylic ester represented byFormula (3x) to obtain a solution including a (meth)acrylic esterrepresented by Formula (1x)

In Formula (2x), Z¹¹ represents an atomic group forming asulfur-containing cyclic hydrocarbon group having 3 to 6 carbon atoms,which includes a carbon atom bonded to a hydroxy group, and —SO₂—.

In Formula (3x), R¹¹ represents a hydrogen atom or a methyl group, andR¹² represents a linear or branched alkyl group having 1 to 10 carbonatoms.

Step 2: step of adding a poor solvent to the solution including the(meth)acrylic ester represented by Formula (1x) obtained in the step 1to precipitate a high-molecular-weight substance, and removing thehigh-molecular-weight substance

[Step 1: Reaction Step]

In the step 1, the compound (1x) is obtained by reacting an alcoholcompound (2x) represented by Formula (2x) with a (meth)acrylic estercompound (3x) represented by Formula (3x).

In the compound (2x), Z¹¹ is an atomic group forming a sulfur-containingcyclic hydrocarbon group having 3 to 6 carbon atoms, which includes acarbon atom bonded to a hydroxy group, and —SO₂—. From the viewpoint ofthe stability of the cyclic structure, the sulfur-containing cyclichydrocarbon group preferably has 4 to 6 carbon atoms. In addition, asubstituent may be bonded to a carbon atom constituting a ring of thesulfur-containing cyclic hydrocarbon group. Examples of the substituentinclude a linear or branched alkyl group having 1 to 10 carbon atoms, ahydroxy group, an amino group, an aldehyde group, a chloro group, abromo group, and an iodo group.

From the viewpoint of easy availability of raw materials, thesulfur-containing cyclic hydrocarbon group is more preferably a2-sulfolane or 3-sulfolane structure in which a ring including asulfonyl group is a 5-membered ring. Among these, a 3-sulfolanestructure is most preferable.

As the compound (2x), 3-hydroxysulfolane is most preferable.

In the compound (3x), R¹¹ is a hydrogen atom or a methyl group, and ispreferably a methyl group.

R¹² is a linear or branched alkyl group having 1 to 10 carbon atoms.Examples of the linear or branched alkyl group having 1 to 10 carbonatoms include a methyl group, an ethyl group, an n-propyl group, anisopropyl group, an n-butyl group, an isobutyl group, a t-butyl group,an n-pentyl group, an n-hexyl group, and a 2-ethylhexyl group.

In the ester exchange reaction, since it is necessary to remove alcoholderived from the raw material ester by distillation, it is preferablethat the boiling point of the by-product alcohol produced by the esterexchange reaction be low. From this viewpoint, R¹² is preferably amethyl group.

That is, as the compound (3x), methyl acrylate or methyl methacrylate ispreferable.

In the step 1, the compound (1x) is produced by the ester exchangereaction. Conditions of the ester exchange reaction are not particularlylimited, and a known method may be performed. For example, JapaneseUnexamined Patent Application, First Publication No. 2007-153763discloses a method of obtaining 3-sulfolanyl methacrylate by reacting3-hydroxysulfolane with methyl methacrylate.

In order to obtain the compound (1x) in good yield, it is preferable todehydrate the compound (2x) before use. As a dehydration method, amethod in which the compound (2x) is dissolved in an organic solvent andthen heated, and water is removed by azeotropy of the organic solventand water is preferable. As the azeotropic organic solvent, benzene,toluene, ethylbenzene, methylethylketone, 1,4-dioxane, hexane,cyclohexane, or the like can be used. In addition, when the compound(3x) is azeotropically boiled with water, it is also possible to performthe dehydration by dissolving the compound (2x) in the compound (3×) andthen azeotropically boiling.

In the ester exchange reaction, a catalyst may or may not be used. Inorder to obtain the compound (1x) in good yield, it is preferable to usea catalyst. When a catalyst is used, a titanium catalyst or a tincatalyst can be used. Examples of the titanium catalyst include titaniumtetramethoxide, titanium tetraethoxide, titanium tetra-n-propoxide,titanium tetraisopropoxide, titanium tetra-n-butoxide, and titaniumtetraisobutoxide. Examples of the tin catalyst include di-n-butyltinoxide, di-n-octyltin oxide, and di-2-ethylhexyltin oxide. From theviewpoint of catalyst removability after reaction, it is preferable touse the titanium catalyst.

From the viewpoint of efficiently obtaining the compound (1x), theamount of the catalyst used is preferably 0.001 mol or more and morepreferably 0.01 mol or more with respect to 1 mol of the compound (2x).In addition, from the viewpoint of catalyst removability and cost, theamount of the catalyst used is preferably 0.05 mol or less and morepreferably 0.03 mol or less with respect to 1 mol of the compound (2x).The ester exchange catalyst may be added all at once or may be added individed portions.

For example, the amount of the catalyst used is preferably 0.001 to 0.05mol and more preferably 0.01 to 0.03 mol with respect to 1 mol of thecompound (2x).

The amount of the compound (3x) used in the ester exchange reaction isnot particularly limited, but from the viewpoint of obtaining thecompound (lx) in good yield, the amount thereof is preferably 0.5 mol ormore, more preferably 0.8 mol or more, and still more preferably 1.0 molor more with respect to 1 mol of the compound (2x). In particular, whenthe by-product alcohol is removed by azeotropy with the compound (3x),since the by-product alcohol cannot be sufficiently removed when theamount of the compound (3x) used is small, the reaction rate maydecrease. In addition, from the viewpoint of suppressing pot efficiencyof the ester exchange reaction and load on the treatment steps after thereaction, the amount of the compound (3x) used is preferably 12 mol orless, more preferably 10 mol or less, and still more preferably 8 mol orless with respect to 1 mol of the compound (2x).

For example, the amount of the compound (3x) used is preferably 0.5 to12 mol, more preferably 0.8 to 10 mol, and still more preferably 1 to 8mol with respect to 1 mol of the compound (2x).

In order to suppress polymerization of the compound (3x) or the compound(1x), it is preferable to add a polymerization inhibitor to the reactionsystem. The type of the polymerization inhibitor is not particularlylimited, and one type may be used or two or more types may be used.

Examples of the polymerization inhibitor include phenolic compounds suchas hydroquinone, p-methoxyphenol, 2,4-dimethyl-6-tert-butylphenol,2,6-tert-butyl-4-methylphenol, tert-butylcatechol, and2,6-di-tert-butyl-4-methylphenol; amine compounds such asN,N-diisopropyl-p-phenylenediamine,N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, andN,N-di-2-naphthylparaphenylenediamine; and N-oxyl compounds such as4-hydroxy-2,2,6,6-tetramethylpiperidin-N-oxyl,4-benzoyloxy-2,2,6,6-tetramethylpiperidin-N-oxyl,4-acetamido-2,2,6,6-tetramethylpiperidin-N-oxyl, andbis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate.

In addition, in order to prevent the polymerization, it is alsopreferable to perform bubbling with an oxygen-containing gas during theester exchange reaction. The amount of the oxygen-containing gas to beintroduced can be set as appropriate. It is particularly preferable touse air as the oxygen-containing gas.

The temperature of the ester exchange reaction is not particularlylimited, but in order to remove the by-product alcohol and improve thereaction rate, the temperature is preferably 30° C. or higher and morepreferably 60° C. or higher. In addition, in order to suppresspolymerization of the compound (3x) or the compound (1x), thetemperature is preferably 160° C. or lower and more preferably 140° C.or lower.

For example, the temperature of the ester exchange reaction ispreferably 30° C. to 160° C. and more preferably 60° C. to 140° C.

From the viewpoint of efficiently obtaining the compound (1x), the timeof the ester exchange reaction is preferably 0.5 hours or more and morepreferably 1 hour or more. In addition, in order to suppresspolymerization of the compound (3x) or the compound (1x), the time ispreferably 50 hours or less and more preferably 30 hours or less.

For example, the time of the ester exchange reaction is preferably 0.5to 50 hours and more preferably 1 to 30 hours.

When a catalyst is used, as a post-treatment after the reaction, anoperation of deactivating the catalyst may be performed. In particular,when the compound (1x) is used for a resist, it is preferable to reducemetal contamination as much as possible. Therefore, when a metal is usedas the catalyst, it is preferable to deactivate and remove the catalyst.An example of a method thereof includes the following method.

That is, after cooling the reaction solution to approximately 70° C. orlower with stirring, the same amount or more of water as the addedcatalyst, an adsorbent, and Celite as a filtration aid are addedthereto, so that the catalyst is turned into a metal oxide to bedeactivated and precipitated. After the addition is completed, stirringis continued for approximately 1 to 5 hours. The precipitated metaloxide can be removed by pressure filtration, filtration under reducedpressure, or the like.

[Step 2: Purification Step]

In the step 2, a poor solvent is added to the solution including thecompound (1x) produced in the step 1 to precipitate ahigh-molecular-weight substance, and the precipitatedhigh-molecular-weight substance is removed. The precipitation of thehigh-molecular-weight substance by the poor solvent in the step 2 is toprecipitate the high-molecular-weight substance without precipitatingthe compound (1x), which is different from a washing operation and arecrystallization operation described later in which thehigh-molecular-weight substance is not precipitated.

The poor solvent to be added is not particularly limited, and examplesthereof include hydrocarbon solvents such as pentane, hexane, heptane,cyclopentane, cyclohexane, octane, toluene, and xylene; ether solventssuch as diethyl ether, diisopropyl ether, t-butylmethyl ether,tetrahydrofuran, and dioxane; ester solvents such as ethyl acetate,butyl acetate, methyl methacrylate, ethyl methacrylate, isopropylmethacrylate, and butyl methacrylate; and alcoholic solvents such asmethanol, ethanol, and 2-propanol. One kind of the poor solvent may beused, or two or more kinds thereof may be mixed and used.

It is more preferable to use a hydrocarbon solvent having a lowsolubility of the high-molecular-weight substance. Among these, from theviewpoint that it is easy to remove by distillation or the like, asaturated hydrocarbon solvent having 5 to 7 carbon atoms such aspentane, hexane, and heptane is still more preferable.

The amount of the poor solvent added can be appropriately determineddepending on the amount of the high-molecular-weight substance and thesolubility. In order to lower the solubility of thehigh-molecular-weight substance to precipitate the high-molecular-weightsubstance, the amount of the poor solvent added is preferably 0.2 masstimes or more and more preferably 0.5 mass times or more with respect tothe mass of the compound (2x) used in the reaction. In addition, fromthe viewpoint of economic efficiency and pot efficiency, the amount ofthe poor solvent added is preferably 5 mass times or less and morepreferably 3 mass times or less with respect to the mass of the compound(2x) used in the reaction.

For example, the amount of the poor solvent added is preferably 0.2 to 5mass times and more preferably 0.5 to 3 mass times with respect to themass of the compound (2x) used in the reaction.

The method for removing the precipitated high-molecular-weight substanceis not particularly limited, and examples thereof include separation asdistillation residue, pressure filtration, filtration under reducedpressure, and centrifugation. An appropriate method may be used inconsideration of the boiling point and properties of the compound (lx),scale, the amount of the high-molecular-weight substance, and the like.In order to prevent the formation of the high-molecular-weight substanceagain in the process of removal, it is desirable to use pressurefiltration, filtration under reduced pressure, or centrifugation, whichis a non-heating method.

After the separation of the high-molecular-weight substance, the poorsolvent may be removed by concentration by vacuum distillation or thelike.

The step 2 may include a purification operation of the compound (1x) asnecessary. Examples of the method for purifying the compound (1x)include washing, heat treatment, filtration, distillation, andrecrystallization. These may be performed individually, or may beperformed in combination of two or more thereof. The purification may beperformed before or after the precipitation step of thehigh-molecular-weight substance, or may be performed both before andafter.

Since the compound (2x) has a sulfonyl group, the compound (2x) has highpolarity and is easily dissolved in water. Therefore, by washing with,as a washing solution, water or an aqueous solution in which 5 to 30mass % of inorganic salts such as sodium chloride, ammonium sulfate, andsodium sulfate are dissolved, the compound (2x) can be removed into theaqueous layer. The number of washings can be appropriately determined.From the viewpoint of reducing contamination of metal in the compound(1x), it is preferable to include a step of washing with water.

The above-described washing may be performed without adding a solvent,or may be performed by diluting with a solvent. In order to reducehydrolysis of the compound (1x) and outflow to the aqueous layer, it ispreferable to dilute with a solvent. The solvent is not particularlylimited, and examples thereof include hydrocarbon solvents such aspentane, hexane, heptane, cyclopentane, cyclohexane, octane, toluene,and xylene; ether solvents such as diethyl ether, diisopropyl ether,t-butylmethyl ether, tetrahydrofuran, and dioxane; and ester solventssuch as ethyl acetate, butyl acetate, methyl methacrylate, ethylmethacrylate, isopropyl methacrylate, and butyl methacrylate. One kindof these solvents may be used, or two or more kinds thereof may be mixedand used. The amount of the solvent to be used can be appropriatelydetermined depending on solubility of the compound (1x) and the amountof the washing solution.

When the compound (1x) is purified by distillation, it is preferable toperform the distillation by adding the polymerization inhibitor andappropriately introducing the oxygen-containing gas such as air at avacuum degree of 1.3 kPa (10 mmHg) or less. In particular, from theviewpoint that heat history is less, it is preferable to perform thedistillation by a method such as thin film distillation.

When the compound (1x) is purified by recrystallization, a solvent inwhich the above-described compound (1x) is dissolved at room temperatureto 40° C. and crystals are precipitated by cooling below roomtemperature is used. As the solvent used for the recrystallization,alcoholic solvents such as methanol, ethanol, isopropanol, and butanol,ester solvents such as ethyl acetate, butyl acetate, and methylmethacrylate, and ether solvents such as diethyl ether, diisopropylether, and t-butylmethyl ether can be used alone, or can be mixed andused. In addition, in order to improve the recovery rate of therecrystallization, a hydrocarbon solvent such as hexane, octane, andheptane, a halogen solvent such as dichloroethane and dichloromethane,water, or the like, in which is difficult to dissolve the crystals, canalso be used by mixing with the above-described alcoholic solvent, theabove-described ester solvent, or the above-described ether solvent.From the viewpoint that the solvent can be easily reused, it ispreferable to use the alcoholic solvent alone. In addition, from theviewpoint of improving the recovery rate by adjusting the slurryconcentration when the crystals are precipitated, a mixed solvent of thealcoholic solvent and the hydrocarbon solvent is more preferable.

From the viewpoint of suppressing an increase in viscosity and improvingprocess passability, the slurry concentration is preferably 25 mass % orless and more preferably 20 mass % or less. In addition, from theviewpoint of economic efficiency and pot efficiency, the slurryconcentration is preferably 5 mass % or more and more preferably 10 mass% or more.

For example, the slurry concentration is preferably 5 to 25 mass % andmore preferably 10 to 20 mass %.

In the recrystallization, it is preferable to promote crystallization bydissolving the compound (1x) in a solvent at 30° C. or higher, graduallycooling the solution, and adding seed crystals when the internaltemperature reached 5° C. to 10° C. With the crystallization, theinternal temperature increases due to latent heat, but when the solutionis cooled and the internal temperature reached 10° C. or lower, thecrystals are separated. The separation of the crystals can be performedusing a centrifugal filter, a pressure filter, or the like. After theseparation of the crystals, the crystals are washed with a solvent.

After the recrystallization, it is preferable that the crystals beseparated using a solvent which is mixed or dissolved in water, and thenthe wet crystal cake be washed with water. As a result, most of thesolvent adhering to the crystals can be removed, and even when thetemperature of the wet crystals increases to around room temperature,there is almost no possibility of melting.

EXAMPLES

Hereinafter, the present invention will be described in more detail withreference to Examples, but the present invention is not limited to theseexamples.

Example (I)

Reaction tracking was performed by gas chromatography.

<Measurement Method of Weight Average Molecular Weight>

The weight average molecular weight (Mw) and molecular weightdistribution (Mw/Mn) of a polymer were determined by gel permeationchromatography in terms of polystyrene. As an eluent, tetrahydrofuran(THF) was used.

<Measurement Method of Copolymerization Composition Ratio>

With regard to polymers obtained in each example, a composition ratio(unit: mol %) of constituent units based on each monomer was determinedby ¹H-NMR measurement.

In the measurement, using an ECS-400 type superconducting FourierTransformation (FT)-NMR device manufactured by JEOL Ltd., approximately5 mass % of a sample solution (solvent was deuterated chloroform) wasplaced in a sample tube having a diameter of 5 mmφ, and integration wasperformed 64 times in a single pulse mode with an observation frequencyof 400 MHz. The measurement temperature was 60° C.

<Evaluation Method of Solubility in Developer (Measurement Method ofTurbidity)>

Using a turbidimeter (manufactured by Orbeco-Hellige, Inc., productname: TB200), a turbidity Th(80) and a turbidity Tm(80) were measured bythe following methods. The Th(80) is an index of solubility in alow-polarity organic solvent, and the Tm(80) is an index of solubilityin a high-polarity organic solvent. As the turbidity becomes higher, thesolubility in an organic solvent becomes lower. In other words, as theturbidity becomes higher, the polarity becomes higher and the solubilityin an alkaline developer is excellent.

[Measurement Method of Turbidity Th(80)]

(1) a polymer to be measured was dissolved in a mixed solvent ofPGMEA/γ-butyrolactone=75/25 mass % to prepare a PGMEA/γ-butyrolactonesolution (hereinafter, referred to as a sample solution) having aconcentration of 20 mass %.

(2) n-heptane was added to the sample solution prepared in (1) toprepare a mixed solution, and the amount of n-heptane added (Xh mass %)to the sample solution when the turbidity of the mixed solution reached10 NTU was determined.

(3) an amount of n-heptane corresponding to 80% of Xh mass % was addedto the sample solution prepared in (1), and the mixture was stirred at25° C. for 4 hours to obtain a measurement solution.

(4) turbidity of the measurement solution at 25° C. was defined asTh(80).

[Measurement Method of Turbidity Tm(80)]

(5) methanol was added to the sample solution prepared in (1) to preparea mixed solution, and the amount of methanol added (Xm mass %) to thesample solution when the turbidity of the mixed solution reached 5.0 NTUwas determined.

(6) an amount of methanol corresponding to 80% of Xm mass % was added tothe sample solution prepared in (1), and the mixture was stirred at 25°C. for 4 hours to obtain a measurement solution.

(7) turbidity of the measurement solution at 25° C. was defined asTm(80).

In the following examples and comparative examples, the followingmonomers (m1) to (m7) were used.

Example 1-1

Into a flask equipped with a nitrogen inlet, a stirrer, a condenser, anda thermometer, 8.1 parts by mass of PGMEA and 32.5 parts by mass ofy-butyrolactone were charged in a nitrogen atmosphere, and thetemperature of a hot water bath was raised to 80° C. while stirring themixture. Thereafter, the following mixture 1 was added dropwise to theflask from a dropping funnel over 4 hours, and the temperature wasfurther maintained at 80° C. for 3 hours to obtain a reaction solution.

(Composition of Mixture 1)

Monomer (m1): 8.17 parts by mass (20 mol %),

Monomer (m2): 10.20 parts by mass (30 mol %),

Monomer (m3): 13.44 parts by mass (40 mol %),

Monomer (m4): 4.72 parts by mass (10 mol %),

Solvent: 8.9 parts by mass of PGMEA and 35.7 parts by mass ofγ-butyrolactone, and

Polymerization initiator: 3.91 parts by mass ofdimethyl-2,2′-azobisisobutyrate (manufactured by Wako Pure ChemicalCorporation, V601 (trade name))

The obtained reaction solution was added dropwise to a mixed solvent ofmethanol and water (methanol/water=80/20 volume ratio) in an amount ofapproximately 10 times while stirring to obtain a white precipitate. Theprecipitate was separated by filtration, and poured again into methanolin the same amount as described above to be washed while stirring. Theprecipitate after washing was filtered off to obtain a polymer wetpowder, and the polymer wet powder was dried under reduced pressure at60° C. for approximately 36 hours to obtain a dry powdery polymer.

The weight average molecular weight (Mw) and molecular weightdistribution (Mw/Mn) of the obtained polymer are shown in Table 1 (thesame applies hereinafter).

With regard to the obtained polymer, the turbidity was measured by theabove-described method. The results are shown in Table 1 (the sameapplies hereinafter).

The copolymerization composition ratio shown in Table 1 is a chargingratio, but when the copolymerization composition ratio of the obtainedpolymer was measured by the above-described method, the constituent unit(m1) was 20.2 mol %, the constituent unit (m2) was 30.1 mol %, theconstituent unit (m3) was 39.7 mol %, and the constituent unit (m4) was10.0 mol %, which were almost the same as the charging ratio.

15.0 parts by mass of the dry powdery polymer obtained above, 105.0parts by mass of PGMEA, and 0.3 parts by mass of triphenylsulfoniumtriflate, which is a photoacid generator, were mixed to a uniformsolution, and then the mixture was filtered with a membrane filterhaving a pore size of 0.1 μm to produce a resist composition.

Example 1-2 and Comparative Example 1-1

The charged composition of the monomer in Example 1-1 was changed asshown in Table 1. Polymers were produced and evaluated in the samemanner as in Example 1-1.

In addition, using the obtained polymers, resist compositions wereproduced in the same manner as in Example 1-1.

Comparative Examples 2-1 and 2-2

The charged composition of the monomer in Example 1-1 was changed asshown in Table 1. Polymers were produced and evaluated in the samemanner as in Example 1-1.

In addition, using the obtained polymers, resist compositions wereproduced in the same manner as in Example 1-1.

Examples 3-1 and 4-1, and Comparative Example 3-1

The charged composition of the monomer in Example 1-1 was changed asshown in Table 1. Polymers were produced and evaluated in the samemanner as in Example 1-1.

In addition, using the obtained polymers, resist compositions wereproduced in the same manner as in Example 1-1.

TABLE 1 Composition of monomer (molar ratio) Molecular weight Turbidity(NTU) m1 m2 m3 m4 m5 m6 m7 Mw Mw/Mn Th(80) Tm(80) Example 1-1 20 30 4010 — — — 9700 1.76 6.9 4.4 Example 1-2 60 — 40 — — — — 9700 1.77 6.4 4.0Comparative — 60 40 — — — — 9600 1.80 4.0 3.4 Example 1-1 Comparative 2030 — 10 40 — — 9500 1.82 5.3 3.6 Example 2-1 Comparative 60 — — — 40 — —9600 1.79 5.5 3.6 Example 2-2 Example 3-1 20 30 20 — 30 — — 9800 1.785.7 3.7 Comparative 20 30 10 — 40 — — 9700 1.77 5.4 3.5 Example 3-1Example 4-1 30 — — — — 40 30 9700 1.80 7.3 4.4

As shown in Table 1, since the polymers of Examples 1-1, 1-2, 3-1, and4-1 had high turbidity, the polymers had high polarity and had excellentsolubility in an alkaline developer.

Example (II)

In the following examples and comparative examples, 3-hydroxysulfolanesynthesized according to the method of Patent Document 1 (JapaneseUnexamined Patent Application, First Publication No. 2007-153763) wasused.

As methyl methacrylate, ACRYESTER M (product name) manufactured byMitsubishi Chemical Corporation was used.

As titanium tetrabutoxide, titanium tetrabutoxide manufactured by KANTOCHEMICAL CO., INC. was used.

As 4-hydroxy-2,2,6,6-tetramethylpiperidin-N-oxyl,4-hydroxy-2,2,6,6-tetramethylpiperidin-N-oxyl manufactured by FujifilmWako Pure Chemical Corporation was used.

As Celite, Celite 545 (product name) manufactured by Kishida ChemicalCo., Ltd. was used.

The reaction rate in the ester exchange reaction was calculated by thefollowing expression from a peak area measured by a gas chromatograph(hereinafter, referred to as “GC”; equipment: Agilent 6890GC of AgilentTechnologies, Inc., column: HP-5).

Reaction rate (%)=(A/B)×100

Here, A represents a quantitative value of a compound (1) by acalibration curve, and B represents the total of quantitative values ofthe compound (1) and a compound (2) by the calibration curve.

The content of the high-molecular-weight substance was calculated by aquantitative value by a calibration curve from a peak area valuemeasured by gel permeation chromatography (hereinafter, referred to as“GPC”; equipment: HLC-8320GPC of Tosoh Corporation, column: ShodexLF-804 (3 pieces), eluent: tetrahydrofuran).

The weight average molecular weight (Mw) of the high-molecular-weightsubstance was calculated from an elution time measured by GPC(equipment: HLC-8320GPC of Tosoh Corporation, column: Shodex LF-804 (3pieces), eluent: tetrahydrofuran) using a calibration curve withstandard polystyrene.

Example 5-1

[Step 1]

Into a 100 mL glass flask equipped with Dean-Stark, 20.1 g (147 mmol) of3-hydroxysulfolane, 103.1 g (1.0 mol) of methyl methacrylate, and 0.12 gof 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (hereinafter, referredto as “HO-TEMPO) were charged, the solution was heated to reflux, andthe water content in the solution was removed by the Dean-Stark. Next,1.5 g (4 mmol) of titanium tetrabutoxide was added thereto, and whileblowing air at 20 mL/min, the reaction solution was heated to reflux atan internal temperature of 100° C. to 110° C. While methanol produced bythe reaction was removed by azeotropy with the methyl methacrylate usingthe Dean-Stark, the reaction solution was stirred for 2.5 hours. Theamount of the mixed solution of methanol and methyl methacrylateextracted during this period was 45.8 g. The reaction rate by GCanalysis was 91%. Thereafter, after cooling to room temperature, 1.6 gof water and 6.9 g of Celite were added thereto, the mixture was stirredfor 1 hour, and the obtained mixed solution was filtered under reducedpressure with a filter paper. When GPC analysis and Mw measurement wereperformed, 1.15 mass % of a high-molecular-weight substance of Mw4.6×10⁵ was detected.

[Step 2]

30 mL of toluene was added to the obtained filtrate, 15 mL of water wasadded to wash the organic layer, and the aqueous layer was dischargedusing a separatory funnel. Thereafter, 20 mL of water was added to washthe organic layer, and the aqueous layer was discharged using aseparatory funnel. Next, 24 g of hexane was added thereto, and themixture was stirred to precipitate a gel-like high-molecular-weightsubstance. After adding magnesium sulfate to dry, the mixture wasfiltered under reduced pressure using a filter paper, and the filtratewas concentrated using an evaporator to obtain 22.1 g of crude3-sulfolanyl methacrylate. As a result of GPC analysis, nohigh-molecular-weight substance having a molecular weight of 5000 ormore was detected.

66.2 g of 2-propanol and 33.1 g of heptane were added to the obtainedcrude 3-sulfolanyl methacrylate, the mixture was cooled while stirring,and seed crystals were added at a temperature below 20° C. toprecipitate crystals. The obtained crystals were filtered, washed withheptane and water, and dried under reduced pressure to obtain 12.9 g ofpurified 3-sulfolanyl methacrylate. As a result of GPC analysis, nohigh-molecular-weight substance having a molecular weight of 5000 ormore was detected.

Example 5-2

[Step 1]

Into a 3 L glass flask equipped with a stirrer, a thermometer, andDean-Stark, 351 g (2.6 mol) of 3-hydroxysulfolane, 1770 g (17.7 mol) ofmethyl methacrylate, and 2.2 g of HO-TEMPO were charged, the solutionwas heated to reflux, and the water content in the solution was removedby the Dean-Stark. Next, 26 g (77 mmol) of titanium tetrabutoxide wasadded thereto, and while blowing air at 20 mL/min, the reaction solutionwas heated to reflux at an internal temperature of 100° C. to 110° C.While methanol produced by the reaction was removed by azeotropy withthe methyl methacrylate using the Dean-Stark, the reaction solution wasstirred for 8 hours. The amount of the mixed solution of methanol andmethyl methacrylate extracted during this period was 902 g. The reactionrate by GC analysis was 88%. Thereafter, after cooling to roomtemperature, 28 g of water and 121 g of Celite were added thereto, themixture was stirred for 1 hour, and the obtained mixed solution wasfiltered under reduced pressure with a filter paper. When GPC analysisand Mw measurement were performed, 0.08 mass % of ahigh-molecular-weight substance of Mw 4.0×10⁵ was detected.

[Step 2]

900 mL of toluene was added to the obtained filtrate and 200 mL of waterwas added to wash the organic layer, so that 242 g of the aqueous layerwas separated. Next, 200 mL of water was added to wash the organiclayer, so that 204 g of the aqueous layer was separated. Next, 650 mL ofhexane was added thereto, and the mixture was stirred to precipitate agel-like high-molecular-weight substance. After adding magnesium sulfateto dry, the mixture was filtered under reduced pressure using a filterpaper, and the filtrate was concentrated using an evaporator to obtain406 g of crude 3-sulfolanyl methacrylate. As a result of GPC analysis,no high-molecular-weight substance having a molecular weight of 5000 ormore was detected.

While keeping the obtained crude 3-sulfolanyl methacrylate at 26° C.,1181 g of 2-propanol and 592 g of heptane were added thereto, themixture was cooled while stirring, and seed crystals were added at atemperature below 20° C. to precipitate crystals. The obtained crystalswere filtered, washed with heptane and water, and dried under reducedpressure to obtain 219 g of purified 3-sulfolanyl methacrylate. As aresult of GPC analysis, no high-molecular-weight substance having amolecular weight of 5000 or more was detected.

Example 5-3

[Step 1]

Into a 10 L glass separable flask equipped with a stirrer, athermometer, and Dean-Stark, 1394 g (10.2 mol) of 3-hydroxysulfolane,7269 g (72.6 mol) of methyl methacrylate, and 4.4 g of HO-TEMPO werecharged, the solution was heated to reflux, and the water content in thesolution was removed by the Dean-Stark. Next, 70 g (0.2 mol) of titaniumtetrabutoxide was added thereto, and while blowing air at 20 mL/min, thereaction solution was heated to reflux at an internal temperature of100° C. to 110° C. While methanol produced by the reaction was removedby azeotropy with the methyl methacrylate using the Dean-Stark, thereaction solution was stirred for 6 hours. The amount of the mixedsolution of methanol and methyl methacrylate extracted during thisperiod was 1477 g. The reaction rate by GC analysis was 67%. Next, thereaction solution was cooled to 70° C. or lower, 35 g (0.1 mol) oftitanium tetrabutoxide was added thereto, and while blowing air at 20mL/min, the reaction solution was heated to reflux at an internaltemperature of 100° C. to 110° C. While methanol produced by thereaction was removed by azeotropy with the methyl methacrylate using theDean-Stark, the reaction solution was stirred for 7.5 hours. The amountof the mixed solution of methanol and methyl methacrylate extractedduring this period was 2081 g. The reaction rate by GC analysis was 87%.The reaction solution was cooled to 70° C. or lower again, 3.5 g (0.01mol) of titanium tetrabutoxide was added thereto, and while blowing airat 20 mL/min, the reaction solution was heated to reflux at an internaltemperature of 100° C. to 110° C. The stirring was continued for 3.5hours, but the reaction rate by GC analysis was 87%. The amount of themixed solution of methanol and methyl methacrylate extracted during thisperiod was 525 g. Thereafter, after cooling to 70° C. or lower, 16 g ofwater and 483 g of Celite were added thereto, the mixture was stirredfor 1 hour, and the obtained mixed solution was filtered under pressurewith a filter paper. When GPC analysis and Mw measurement wereperformed, 0.21 mass % of a high-molecular-weight substance of Mw4.2×10⁵ was detected.

[Step 2]

3000 g of toluene was added to the obtained filtrate and 812 g of waterwas added to wash the organic layer, so that 965 g of the aqueous layerwas separated. Next, 837 g of water was added to wash the organic layer,so that 852 g of the aqueous layer was separated. Next, 2020 g of hexanewas added thereto, and the mixture was stirred to precipitate a gel-likehigh-molecular-weight substance. The high-molecular-weight substance wasremoved by pressure filtration with a filter paper, and the filtrate wasconcentrated using an evaporator to obtain 1641 g of crude 3-sulfolanylmethacrylate. As a result of GPC analysis, no high-molecular-weightsubstance having a molecular weight of 5000 or more was detected.

While keeping the obtained crude 3-sulfolanyl methacrylate at 22° C.,4690 g of 2-propanol and 2380 g of heptane were added thereto, themixture was cooled while stirring, and seed crystals were added at atemperature below 17° C. to precipitate crystals. The obtained crystalswere filtered, washed with heptane and water, and dried under reducedpressure to obtain 1000 g of purified 3-sulfolanyl methacrylate. As aresult of GPC analysis, no high-molecular-weight substance having amolecular weight of 5000 or more was detected.

Comparative Example 5-1

Using 20.0 g (147 mmol) of 3-hydroxysulfolane, 118.0 g (1.2 mol) ofmethyl methacrylate, 0.12 g of HO-TEMPO, and 0.7 g (4 mmol) of titaniumtetraethoxide, the step 1 was performed in the same manner as in Example5-1. When GPC analysis and Mw measurement of the filtrate wereperformed, 0.29 mass % of a high-molecular-weight substance of Mw4.8×10⁵ was detected.

30 mL of toluene was added to the obtained filtrate, 15 mL of water wasadded to wash the organic layer, and the aqueous layer was dischargedusing a separatory funnel. Thereafter, 15 mL of water was added to washthe organic layer, and the aqueous layer was discharged using aseparatory funnel. After adding magnesium sulfate to dry, the mixturewas filtered under reduced pressure using a filter paper, and thefiltrate was concentrated using an evaporator to obtain 25.6 g of crude3-sulfolanyl methacrylate. As a result of GPC analysis, 0.22 mass % ofthe high-molecular-weight substance was detected. When 38.9 g of2-propanol was added to the crude 3-sulfolanyl methacrylate, a gel-likehigh-molecular-weight substance was precipitated, but in this state,38.4 g of 2-propanol and 38.5 g of heptane were added thereto, and seedcrystals were added at a temperature below 20° C. to performrecrystallization, thereby obtaining 21.3 g of purified 3-sulfolanylmethacrylate. As a result of analysis by GPC, 0.11 mass % of ahigh-molecular-weight substance having a molecular weight of 5000 ormore was detected.

In these examples, the results of Mw measurement and GPC analysis of thehigh-molecular-weight substance in each step are shown in Table 2.

In Table 2, “After step 1” represents the analysis result after thereaction, “After step 2” represents the analysis result after adding thepoor solvent to precipitate and remove the high-molecular-weightsubstance and concentrating the resultant, and “After recrystallizationstep” represents the analysis result of purified 3-sulfolanylmethacrylate obtained by the recrystallization purification.

N. D. means that the high-molecular-weight substance was not detected.

TABLE 2 Content of high-molecular- weight substance (mass %)High-molecular- After weight substance After After recrystallization(Mw) step 1 step 2 step Example 5-1 4.6 × 10⁵ 1.15 N.D. N.D. Example 5-24.0 × 10⁵ 0.08 N.D. N.D. Example 5-3 4.2 × 10⁵ 0.21 N.D. N.D.Comparative 4.8 × 10⁵ 0.29 — 0.11 Example 5-1

As shown in the results in Table 2, the 3-sulfolanyl methacrylatesobtained in Examples 5-1 to 5-3 were of high purity in which thehigh-molecular-weight substance having a molecular weight of 5000 ormore was not detected.

Meanwhile, in Comparative Example 5-1 in which the step 2 was notperformed, the obtained 3-sulfolanyl methacrylate contained 0.11 mass %of the high-molecular-weight substance having a molecular weight of 5000or more.

From these results, it can be seen that a high-molecular-weightsubstance can be removed by precipitating a high-molecular-weightsubstance with a poor solvent in a purification step, and the content ofthe high-molecular-weight substance having a molecular weight of 5000 ormore can be reduced to 0.1 mass % or less.

INDUSTRIAL APPLICABILITY

According to the present embodiment, a polymer having favorablesolubility in a developer, a resist composition including the polymer,and a method for manufacturing a substrate having a pattern formedtherein using the resist composition are obtained.

According to the present embodiment, a sulfonyl group-containing(meth)acrylic ester in which a high-molecular-weight substance isreduced is obtained.

In the (meth)acrylic ester according to the present embodiment, thecontent of the high-molecular-weight substance is reduced, and the(meth)acrylic ester according to the present embodiment is useful for awide range of applications such as plastics, paints, and adhesives. Inaddition, the (meth)acrylic ester according to the present embodiment issuitable as a monomer constituting a resist polymer, and is useful forimproving lithography characteristics.

1. A polymer comprising: a constituent unit (1) based on a monomerrepresented by Formula (1), wherein a content of a constituent unitbased on a monomer having a polycyclic structure is 35 mol % or less, inFormula (1), R¹ represents a hydrogen atom or a methyl group, A¹represents a linking group including an ester bond, or a single bond,where A¹ has no tertiary carbon atom, and Z¹ represents an atomic groupforming a sulfur-containing cyclic hydrocarbon group having 3 to 6carbon atoms, which includes a carbon atom bonded to A¹, and —SO₂—


2. The polymer according to claim 1, further comprising: a constituentunit (2) having an acid-eliminating group.
 3. The polymer according toclaim 2, wherein the constituent unit (2) includes a constituent unit(2i) which has an acid-eliminating group including an alicyclichydrocarbon group.
 4. The polymer according to claim 3, wherein theconstituent unit (2) includes a constituent unit (2ii) which has anacid-eliminating group including a monocyclic alicyclic hydrocarbongroup.
 5. The polymer according to claim 1, wherein the constituent unit(1) is 15 mol % or more with respect to all constituent units.
 6. Thepolymer according to claim 1, further comprising: a constituent unit (3)having a lactone skeleton.
 7. A resist composition comprising: thepolymer according to claim 1; and a compound generating acid byirradiation with active light or radiation.
 8. A method formanufacturing a substrate having a pattern formed therein, comprising: astep of applying the resist composition according to claim 7 to asurface of a substrate to be processed to form a resist film; a step ofexposing the resist film; and a step of developing the exposed resistfilm with a developer.
 9. A production method of a (meth)acrylic esterrepresented by Formula (1x), comprising: a step 1: step of performing anester exchange reaction between an alcohol represented by Formula (2x)and a (meth)acrylic ester represented by Formula (3x) to obtain asolution including a (meth)acrylic ester (1x) represented by Formula(1x); and a step 2: step of adding a poor solvent to the solutionincluding the (meth)acrylic ester (1x) obtained in the step 1 toprecipitate a high-molecular-weight substance, and removing thehigh-molecular-weight substance, in Formula (1x), R¹¹ represents ahydrogen atom or a methyl group, A11 represents a linking groupincluding an ester bond, or a single bond, where A¹¹ has no tertiarycarbon atom, and 2¹¹ represents an atomic group forming asulfur-containing cyclic hydrocarbon group having 3 to 6 carbon atoms,which includes a carbon atom bonded to A¹¹, and —SO₂—, in Formula (2x),Z¹¹ represents an atomic group forming a sulfur-containing cyclichydrocarbon group having 3 to 6 carbon atoms, which includes a carbonatom bonded to a hydroxy group, and —SO₂—, and in Formula (3x), R¹¹represents a hydrogen atom or a methyl group, and R¹² represents alinear or branched alkyl group having 1 to 10 carbon atoms


10. The production method of a (meth)acrylic ester according to claim 9,wherein a hydrocarbon solvent is used as the poor solvent in step
 2. 11.A (meth)acrylic ester represented by Formula (1x), wherein a content ofa high-molecular-weight substance having a molecular weight of 5000 ormore is 0.1 mass % or less, in Formula (1x), R¹¹ represents a hydrogenatom or a methyl group, A¹¹ represents a linking group including anester bond, or a single bond, where A¹¹ has no tertiary carbon atom, andZ¹¹ represents an atomic group forming a sulfur-containing cyclichydrocarbon group having 3 to 6 carbon atoms, which includes a carbonatom bonded to A¹¹, and —SO₂—